Questions about building Open ROV

Hey Guys,

I’m interested in building an OpenRoV. I’m aware that the company is not selling new kits. After some research, I saw that the team put everything on Github: OpenROV · GitHub, including BOM and electronica schematics.
I’m an embedded software developer and have some basic electronic knowledge.
Has there been anyone that build the thing from scratch? Where do I begin?

Any advice or tip is welcome.
Thanks in regard